Identification:
Felis
catus, the domestic cat, is one of the smaller members of the
family
Felidae, weighing only five to twenty pounds. Like other members of its
family, the domestic cat is an agile hunter. It has a compact, flexible
body, sharp teeth, retractile claws, and particularly keen eyesight as
evidenced by its large eyes . Long whiskers on the snout detect changes
in its environment and a long tail assists in balance during jumping
and
running. The Cat Fanciers' Association, which claims to have the
largest
registry of pedigreed cats, recognizes forty breeds of domestic cat,
from
the fluffy Persian to the hairless sphynx. A cat's coat may be one or a
combination of a variety of colors, from black, brown, or gray to red,
white, tan or even blue. Cats are either solid in color, have patches
of
different colors, or have "tabby" stripes reminiscent of their wild
ancestors.

The domestic cat is a
close
relative of both Felis silvestris, the European wild cat, and Felis
lybica, the African wild cat. F.catus can interbreed with
both
to produce fertile hybrid offspring. Analysis of mitochondrial
DNA
has shown that F.catus and F.lybica are actually
subspecies
of F.silvestris. Because the three are genetically similar, it
is
often difficult to differentiate one from the other, especially in
regions
where they interbreed. However, generally speaking, F.catus '
domestication
has led to some morphological differences such as smaller brains, jaws,
and teeth than its wild cousins, as well as a wider variety of coat
colors
and lengths.

Original
Distribution: There has been some controversy surrounding the
origin
of the domestic cat. Some suggest the origin lies in Europe from
a hybrid between F. lybica and F.silvestris , while
others
believe it was introduced, already domesticated, to Egypt from Nubia or
Persia. The prevailing opinion is that the cat was domesticated in
Egypt
from local populations of its wild ancestor, F.lybica, in a
domestication
process that began around 6,000 BC.

Current
Distribution:
F.catus
is now distributed worldwide, except for some isolated islands in the
Pacific
southwest where they have not been introduced, or where they have been
introduced but have not established reproducing populations.

Site
and Date of Introduction: The website of the Natural History
Museum
of Los Angeles County presents an excellent map which details the
spread
of the cat from its origins in Egypt circa 6000 BC to present: http://www.lam.mus.ca.us/cats/P27/index.htmIt appears that the
cat's
popularity in Egypt, a country with a major trading port, combined with
its effectiveness as a mouse-hunter, ensured its spread throughout the
world. Cats were introduced to Europe when they were employed as
mousers
aboard Egyptian shipping vessels headed to Rome. They spread to other
parts
of Europe as the Roman Empire expanded, and were taken to Asia along
trade
routes and by missionaries. Later, European colonization brought the
cat
to almost every other part of the globe.

Mode(s) of
Introduction:
In modern times, introduction to a given area is accomplished when a
human
adopts a pet cat and, if kept as an "outdoor" cat, introduces it to the
habitat near their home. This is also the case with "working cats" who
are employed as mousers on farms. In addition, other pet cats are
released
purposely by owners or become lost from home and begin breeding with
other
cats to form feral populations in the area.

Reason(s)
Why it has Become Established: Cats still have the effective
predatory
tools -- such as excellent eyesight and hearing, sharp claws and teeth,
strength, agility -- that made its progenitor, F. lybica , so
successful
in the wild. In addition, cats are prey-generalists; they will eat
almost
any type of animal they encounter, if within their (wide) prey-size
range.
They will even eat insects. Cats are also assisted by their association
with humans. Ferals are known to congregate in areas where food waste
is
contained, such as alleyways and backs of restaurants, where they can
obtain
food in the form of refuse or rodents that are attracted to the refuse.
In addition, cats reproduce very rapidly. Just one fertile female and
her
offspring, under ideal conditions, have the ability to produce
420,000
cats in a seven year period. The cat's hunting prowess and its
likelihood
of finding suitable prey, combined with its ability to thrive in the
midst
of human civilization and its high reproductive rate, makes it
potentially
successful in many habitat types, and therefore highly likely to become
established.

Ecological
Role: Although some "cat-philic" organizations insist that cats
have
been mistakenly vilified as native-species killers, it is apparent they
do much damage in the ecosystems to which they are introduced. Cats
prey
upon birds, small mammals, reptiles, and amphibians whether or not they
are given meals by human owners. Throughout their domestication, cats
have
become more dependent on their human owners for food, but since they
have
specific nutritional requirements that can only be met by fresh meat
(and
recently in the West, by high-quality commercial cat food), cats have
retained
their wild ancestors' ability and instinct to hunt. One estimate
numbers
the US cat population at 93 million (30 million feral and 63 million
pet)
and states that cats are responsible for killing 566 million birds each
year. Other estimates put the feral cat population at 60 million and
the
pet cat population at 73 million. In one Swiss study on the impact of
cats
on a population of black redstarts, Phoenicurus ochruros ,
scientists
found that cat predation reduced the population by 12% in three years
by
causing large numbers of egg and nestling fatalities. Another study of
the impact of exotic species on seabirds on the California Channel
Islands
and northwestern Baja California Islands found that, of several
exotics,
cats had the greatest impact on seabirds; they are responsible the for
the extinction of the Guadalupe storm petrel (Oceanodrama
macrodactyla
) and for eliminating populations of three other seabirds. Whatever
population
estimate one chooses to adhere to, it is clear the number of cats is in
the tens of millions and undoubtedly has an immense impact on our
native
ecosystems.

Benefit(s):
Cats
were first domesticated to serve as pest control agents, keeping levels
of rodents in check at food storage facilities, particularly farms.
They
are still used for this purpose in many locations. In the US, cats may
serve an important role in keeping levels of other invasive species
down
as they do in Australia where, in one study, 64% of cats' prey was
introduced
mammals. The benefit of cats as a companion animal cannot be overlooked
as this has a direct relationship with its ability to spread across the
globe. In 1996 the cat passed the dog in popularity as a household pet.

Threat(s):
Cats threaten wildlife in a variety of ways. They act as a disease
vector
of feline diseases such as feline leukemia and FIV (the feline version
of HIV) to wild cat populations in Europe and Africa and they
interbreed
with wild cat populations which may reduce the genetic fitness of those
populations. Cats are a vector for rabies which they can then spread to
humans, domestic animals, and wildlife such as raccoons. Cats pose a
particularly
major threat to both native birds and small mammals. The Audubon
Society estimates that several billion small animals are killed
annually within the continental United States by house cats and feral
cats. On the islands of Australia, New Zealand,
and Mauritius, the cat is responsible for exterminating several native
bird species. A less serious, though definitely unpleasant, situation
which
cats can create is that of a nearby feral cat population. These
populations
are known for being noisy, especially when females are in heat, and for
creating messy, unsanitary conditions.

Control
Level Diagnosis: Highest Priority. The World Conservation Union has
ranked the domestic cat on its infamous list of "100 of the World's
Worst
Invasive Alien Species." Its continued presence in geographic areas to
which it has been introduced may have even more devastating effects on
native fauna.

Control Method: Several
different methods of cat population control have been attempted. Most
towns
in the US have an animal control division or animal shelter which
accepts
lost and feral cats. Most of these agencies euthanize large numbers of
cats regularly. The Humane Society of the United States estimates that
several million cats are euthanized in the US each year. This method is
tantamount to placing a bandage over the hemorrhaging wound of cat
population
growth. Other attempts have met with somewhat more success. On Marion
Island,
off the coast of southern Africa, domestic cats were eventually
exterminated
after several years of hunting, trapping and poisoning. However, for
any
population not restricted to a small island, extermination by these
methods
is impractical because areas where cats have been exterminated will be
quickly repopulated by nearby source populations. It appears that the
best
way to control feral populations is via a region-wide, comprehensive
program
with the goal of sterilizing the cats in the area without removing them
from that area. Allowing a sterilized cat to live in its area ensures
competition
with neighboring cats for food and space resources which means fewer
kittens
will survive to adulthood to breed. Reducing the number of future
litters
by the combination of sterilization and competition should, albeit
slowly,
reduce the cat population. Many humane-treatment organizations advocate
this "trap-neuter-release" method and are actively involved in
employing
it. The Feral Cat Coalition of San Diego, California provides
marathon-type
neutering clinics for ferals. They claim that there has been about a
50%
drop in cat impounds at the San Diego Department of Animal Control
since
they began their program in 1992.

However, even if we
are able
to eliminate the feral cat population, we still have to deal with the
ecological
effects of millions of pet cats. Since most mammals are nocturnal,
somesuggest
keeping cats indoors at night to protect native mammal populations.
Unfortunately,
this will do nothing to help protect diurnal bird and reptile species.
Attaching a bell to the collar of one's cat may help, but only
temporarily,
as cats can learn to move so as not to ring the bell. Innovations in
bell-type
technologies could be of help, such as electronic alarms attached to
collars
that sound intermittently to warn potential prey of a nearby cat.
Another
option is to keep cats indoors permanently.

Part of the pet cat
population
problem is that there are too few regulations for cats and not
sufficient
incentives for sterilizing cats. For instance, in New York City, it is
required by law that dogs be licensed, however, cat licensing is not
required.
Differential licensing laws where higher fees are charged to owners of
non-neutered cats would encourage neutering. A "cat at-large" law, such
as they have in Fort Collins, Colorado, would encourage owners to act
more
responsibly in controlling their cats whereabouts and interactions with
other cats. This law restricts cats to their owners' property; any cat
not on its owner's property can be picked up by the animal control
agency.
Subsidizing neutering costs can also help in encouraging owners to
sterilize
their cats.

We must confront the
cat
population problem with a combination of methods: enlist the
"trap-neuter-release"
style of feral management and combine it with incentives for owners to
sterilize their pet cats. Ecological consequences of the presence
of cats should be mitigated by restricting pet cats to the indoors or
attaching
an effective bell to the cat to warn potential wildlife prey.

In addition, we have
to consider
that reducing cats' effect on the ecosystem may actually have a
negative
impact upon some native species due to the possibility of "mesopredator
release effect". In areas where domestic cats are preying upon invasive
rodent species, such as the Norway rat, elimination of cats could
induce
a rat population spike which may adversely affect those native fauna
and
flora that are the rats' source of food. Therefore, domestic cat
population
control in a given area should be undertaken with care and an
understanding
of the cat's role in that particular ecosystem.